Electrical conductivity and DFT investigations of a 2D CuI-TCNQII− framework

Abstract

An investigation of the coordination polymer, [Cu₂(Me₂pz)(TCNQ)] (Me₂pz = 2,5-dimethylpyrazine) is described. The structure of [Cu₂(Me₂pz)(TCNQ)] is comprised of 2D sheets with mean plane sheet-to-sheet separations closer than that of graphene sheets in graphite. Electrical conducticity measurements on the framework indicate semiconductor behaviour with a σ_300K = 9.8 × 10⁻⁸ S cm⁻¹ and an E_a = 0.43(3) eV. Density functional theory studies reveal a band structure comprised predominatly by donor TCNQ and acceptor Me₂pz ligand-p oribtals. This investigation also resulted in the formation of Cu(TCNQ) (phase I) from the reaction mixture that yielded [Cu₂(TCNQ)(Me₂pz)]. A redetermination of the crystal structure of Cu(TCNQ) is reported.